Sealed refrigerant compressor and refrigeration device including same

ABSTRACT

A sealed refrigerant compressor (100) includes: a compression element (107) accommodated in a sealed container (101) and configured to compress a refrigerant; and an electric element (106) configured to drive the compression element (107). Lubricating oil (103) is stored in the sealed container (101). A resin member is included as a member accommodated in the sealed container (101). The amount of oligomer contained in the resin member is 2.5 wt. % or less of an entire weight of the resin member. Kinetic viscosity of the lubricating oil 103 at 40° C. falls within a range of 0.1 to 5.1 mm2/s. A flash point of the lubricating oil 103 is 110° C. or more.

TECHNICAL FIELD

The present invention relates to a sealed refrigerant compressor which uses low-viscosity lubricating oil and has high reliability, and a refrigeration device including the sealed refrigerant compressor.

BACKGROUND ART

Highly efficient refrigerant compressors which reduce the use of fossil fuels from the viewpoint of the protection of the global environment have been developed in recent years. For example, in order to increase the efficiency of the refrigerant compressors, proposed is the use of lubricating oil having lower viscosity.

For example, each of PTLs 1 and 2 discloses a specific composition containing ester, as a freezer lubricating oil composition having low viscosity, high lubricity, and excellent long term stability in a low temperature range. Kinetic viscosity of the lubricating oil composition at 40° C. falls within a range of 6 to 28 mm²/s.

According to the sealed refrigerant compressor, members made of resin (resin members) are included as internal members accommodated in the sealed container. The resin constituting the resin members, i.e., polymeric materials constituting the resin members contain not only polymer components but also low molecular components, such as oligomer. It is known that when lubricating oil having lower viscosity is used, the low molecular components, such as oligomer, contained in the resin members are extracted by the lubricating oil, and this deteriorates the reliability of the refrigerant compressor.

Specifically, the oligomer extracted by the lubricating oil adheres to, for example, a suction reed. When the oligomer is carbonized at high temperature, the oligomer may become oil sludge, and the oil sludge may be deposited on the suction reed. This may deteriorate seal performance of the suction reed. Further, if the oligomer extracted by the lubricating oil is fed to a high-pressure side of a refrigeration cycle, a capillary tube of the refrigeration cycle may be clogged, and this may reduce the amount of refrigerant that is circulating.

Therefore, for example, PTL 3 discloses that when using the oil (lubricating oil) having low viscosity set such that the kinetic viscosity at 40° C. is 8 mm²/s or less, the amount of extractable low molecular components contained in the resin member is set to 0.1 parts by weight or less. PTL 3 describes that as Examples, the kinetic viscosity at 40° C. is 10 mm²/s, 8 mm²/s, or 5 mm²/s.

CITATION LIST Patent Literature

PTL 1: Japanese Laid-Open Patent Application Publication No. 2006-160781

PTL 2: Japanese Laid-Open Patent Application Publication No. 2006-328275

PTL 3: Japanese Laid-Open Patent Application Publication No. 2007-239632

SUMMARY OF INVENTION Technical Problem

That the lubricating oil having viscosity lower than lower limits of the ranges of the kinetic viscosities disclosed in PTLs 1 to 3 is used as the lubricating oil for the refrigerant compressors have been considered recently.

When the lubricating oil having lower viscosity is used, the oligomer contained in the resin member is more easily extracted. Thus, a possibility that the deterioration of the seal performance of the suction reed, the clogging of the capillary tube, and the like occur may increase. As a result, the reliability of the refrigerant compressor may further deteriorate.

The present invention was made to solve the above problems, and an object of the present invention is to provide a sealed refrigerant compressor capable of realizing high reliability even when lubricating oil having low viscosity is used, and a refrigeration device including the sealed refrigerant compressor.

Solution to Problem

To solve the above problems, a sealed refrigerant compressor according to the present invention includes: a compression element accommodated in a sealed container and configured to compress a refrigerant; and an electric element configured to drive the compression element. Lubricating oil is stored in the sealed container. A resin member is included as a member accommodated in the sealed container. An amount of oligomer contained in the resin member is 2.5 wt. % or less of an entire weight of the resin member. Kinetic viscosity of the lubricating oil at 40° C. falls within a range of 0.1 to 5.1 mm²/s. A flash point of the lubricating oil is 110° C. or more.

According to the above configuration, the amount of oligomer in the resin member in the sealed container is limited, and the lubricating oil in which the kinetic viscosity falls within the above range and the lower limit of the flash point is the above value is used. As long as the lubricating oil has a relatively high flash point even when the lubricating oil has low viscosity, the lubricating oil hardly permeates the resin member. Therefore, the oligomer is hardly extracted from the resin member. On this account, even when the lubricating oil having low viscosity is used, the resin member containing a relatively larger amount of oligomer than before can be used, and a possibility that the deterioration of the seal performance of the suction reed, the clogging of the capillary tube, and the like occur due to the extraction of the oligomer can be effectively suppressed. As a result, even when the lubricating oil having the low viscosity is used, the reliability of the sealed refrigerant compressor can be made satisfactory.

Further, the present invention includes a refrigeration device including the sealed refrigerant compressor configured as above. Therefore, the present invention can provide the refrigeration device having high reliability.

Advantageous Effects of Invention

By the above configurations, the present invention has an effect of being able to provide a sealed refrigerant compressor capable of realizing high reliability even when lubricating oil having low viscosity is used, and a refrigeration device including such sealed refrigerant compressor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic sectional view showing one example of a typical configuration of a sealed refrigerant compressor according to Embodiment 1 of the present disclosure.

FIG. 2 is a schematic diagram showing one example of a typical configuration of a refrigeration device according to Embodiment 2 of the present disclosure.

DESCRIPTION OF EMBODIMENTS

A sealed refrigerant compressor according to the present disclosure includes: a compression element accommodated in a sealed container and configured to compress a refrigerant; and an electric element configured to drive the compression element. Lubricating oil is stored in the sealed container. A resin member is included as a member accommodated in the sealed container. An amount of oligomer contained in the resin member is 2.5 wt. % or less of an entire weight of the resin member. Kinetic viscosity of the lubricating oil at 40° C. falls within a range of 0.1 to 5.1 mm²/s. A flash point of the lubricating oil is 110° C. or more.

According to the above configuration, the amount of oligomer in the resin member in the sealed container is limited, and the lubricating oil in which the kinetic viscosity falls within the above range and the lower limit of the flash point is the above value is used. As long as the lubricating oil has a relatively high flash point even when the lubricating oil has low viscosity, the lubricating oil hardly permeates the resin member. Therefore, the oligomer is hardly extracted from the resin member. On this account, even when the lubricating oil having low viscosity is used, the resin member containing a relatively larger amount of oligomer than before can be used, and a possibility that the deterioration of the seal performance of the suction reed, the clogging of the capillary tube, and the like occur due to the extraction of the oligomer can be effectively suppressed. As a result, even when the lubricating oil having the low viscosity is used, the reliability of the sealed refrigerant compressor can be made satisfactory.

In the sealed refrigerant compressor configured as above, the amount of oligomer may fall within a range of 0.01 to 1 wt. % of the entire weight of the resin member.

According to the above configuration, when the amount of oligomer in the resin member falls within the above range, the oligomer component is further hardly extracted from the resin member.

In the sealed refrigerant compressor configured as above, the oligomer may be dimer, trimer, or tetramer or contain at least one of the dimer, the trimer, and the tetramer.

According to the above configuration, when the oligomer is at least one of the dimer, the trimer, and the tetramer or contains at least one of the dimer, the trimer, and the tetramer, the oligomer is hardly extracted from the resin member by the lubricating oil having low viscosity and high flash point.

In the sealed refrigerant compressor configured as above, at least a stabilizing agent may be added as an additive to the lubricating oil, and a content of the stabilizing agent added may fall within a range of 0.1 to 10 wt. % of an entire amount of the lubricating oil.

According to the above configuration, by adding at least the stabilizing agent to the lubricating oil, the stability of the lubricating oil can be made satisfactory, and the reliability of the sealed refrigerant compressor can be improved.

In the sealed refrigerant compressor configured as above, the stabilizing agent may be at least one of an acid capturing agent and fullerene.

According to the above configuration, when the stabilizing agent is the acid capturing agent, the fullerene, or a combination of the acid capturing agent and the fullerene, the stability of the lubricating oil can be made more satisfactory, and the reliability of the sealed refrigerant compressor can be improved.

In the sealed refrigerant compressor configured as above, when the stabilizing agent is the fullerene, the content of the fullerene may fall within a range of 0.1 to 5 wt. % of the entire amount of the lubricating oil.

According to the above configuration, when the content of the fullerene added as the stabilizing agent falls within the above range, the stability of the lubricating oil can be made more satisfactory by the fullerene, and the reliability of the sealed refrigerant compressor can be improved.

In the sealed refrigerant compressor configured as above, density of the resin member may fall within a range of 1.2 to 3.0 g/cm³.

According to the above configuration, even when the density of the resin member falls within the above range, the oligomer is hardly extracted from the resin member by the lubricating oil having low viscosity and high flash point.

Further, a refrigeration device according to the present disclosure includes any one of the sealed refrigerant compressors configured as above. With this, the refrigeration device includes the sealed refrigerant compressor having high reliability even when the lubricating oil having low viscosity is used, and therefore, the present invention can provide the refrigeration device having high reliability.

Hereinafter, typical embodiments of the present invention will be described with reference to the drawings. In the following description and the drawings, the same reference signs are used for the same or corresponding members, and a repetition of the same explanation is avoided.

Embodiment 1

Configuration of Refrigerant Compressor

First, a typical example of a refrigerant compressor according to Embodiment 1 will be specifically described with referent to FIG. 1. FIG. 1 is a schematic sectional view of a refrigerant compressor 100 according to Embodiment 1.

As shown in FIG. 1, a refrigerant gas 102 is filled in a sealed container 101 of the refrigerant compressor 100, and lubricating oil 103 is stored in a bottom portion of the sealed container 101. In the present disclosure, as described below, for example, a hydrocarbon refrigerant is used as the refrigerant gas 102, and oil having low viscosity and high flash point is used as the lubricating oil 103. An electric element 106 and a compression element 107 are accommodated in the sealed container 101. The electric element 106 is constituted by a stator 104 and a rotor 105. The compression element 107 is a reciprocating type driven by the electric element 106.

The compression element 107 is constituted by a crank shaft 108, a cylinder block 112, a piston 115, and the like. The configuration of the compression element 107 will be described below.

The crank shaft 108 is constituted by at least a main shaft 109 and an eccentric shaft 110. The main shaft 109 is press-fitted and fixed to the rotor 105. The eccentric shaft 110 is formed eccentrically with respect to the main shaft 109. An oil supply pump 111 communicating with the lubricating oil 103 is provided at a lower end of the crank shaft 108.

The cylinder block 112 is made of cast iron. The cylinder block 112 forms a substantially cylindrical bore 113 and includes a bearing 114 supporting the main shaft 109.

The rotor 105 includes a flange surface 116, and an upper end surface of the bearing 114 is a thrust surface 117. A thrust washer 118 is inserted between the flange surface 116 and the thrust surface 117 of the bearing 114. The flange surface 116, the thrust surface 117, and the thrust washer 118 constitute a thrust bearing 119.

The piston 115 is loosely fitted into the bore 113 with a certain amount of clearance and is made of an iron-based material. The piston 115 forms a compression chamber 120 together with the bore 113. The piston 115 is coupled to the eccentric shaft 110 by a connecting rod 122 as a coupler through a piston pin 121. An end surface of the bore 113 is sealed by a valve plate 123.

A head 124 forms a high pressure chamber. The head 124 is fixed to the valve plate 123 at an opposite side of the bore 113. A suction tube (not shown) is fixed to the sealed container 101 and connected to a low-pressure side (not shown) of a refrigeration cycle. The suction tube introduces the refrigerant gas 102 into the sealed container 101. A suction muffler 125 is sandwiched between the valve plate 123 and the head 124.

A cluster 127 is connected through a lead wire 126 to the stator 104 constituting the electric element 106. A terminal 128 is provided at the sealed container 101 so as to penetrate the sealed container 101 from inside to outside. The cluster 127 is coupled to the terminal 128. With this, electric power is supplied from a commercial power supply (not shown) to the electric element 106.

The type of the refrigerant gas 102 used in the refrigerant compressor 100 according to the present disclosure is not especially limited, but the above-described hydrocarbon refrigerant is preferably used. Specific examples of the hydrocarbon refrigerant include R290 (propane), R600a (isobutane), R600 (butane), and R1270 (propylene), but the hydrocarbon refrigerant is not especially limited. Typical examples of the hydrocarbon refrigerant include R600a and R290.

As described below, the refrigerant compressor 100 according to the present disclosure uses the lubricating oil 103 having low viscosity and a high flash point. As described above, the lubricating oil 103 is mixed oil constituted by mineral oil and synthetic oil. The refrigerant gas 102 is used in a refrigerant circuit (refrigeration cycle; see Embodiment 2) including the refrigerant compressor 100. The refrigerant gas 102 and the lubricating oil 103 exist in the sealed container 101 in a state where the refrigerant gas 102 and the lubricating oil 103 can contact and be mixed with each other. Therefore, the refrigerant gas 102 and the lubricating oil 103 can be regarded as constituting a working medium for the refrigeration cycle. The working medium for the refrigeration cycle contains a refrigerant component and a lubricating oil component and may further contain other components.

In the refrigerant compressor 100 according to the present disclosure, resin members are included as members accommodated in the sealed container 101. The resin members are not especially limited as long as the resin members are constituted by at least resin, i.e., polymer. In the present disclosure, the amount of oligomer contained in the resin member is set to 2.5 wt. % or less of the entire weight of the resin member. Typical examples of the resin members include the suction muffler 125, an insulating member attached to the electric element 106, and the cluster 127. Specific configurations of the resin members will be described below.

One example of operations of the refrigerant compressor 100 according to the present disclosure will be described below. First, electric power is supplied from a commercial power supply (not shown) through the terminal 128 and the cluster 127 to the electric element 106, and this rotates the rotor 105 of the electric element 106. The rotor 105 rotates the crank shaft 108, and an eccentric motion of the eccentric shaft 110 drives the piston 115 through the connecting rod 122 as the coupler and the piston pin 121.

The piston 115 reciprocates in the bore 113, and with this, the refrigerant gas 102 introduced into the sealed container 101 through the suction tube (not shown) is sucked from the suction muffler 125 and compressed in the compression chamber 120. In accordance with the rotation of the crank shaft 108, the lubricating oil 103 is supplied from the oil supply pump 111 to respective slide portions. Thus, the slide portions are lubricated, and the lubricating oil 103 serves as a seal between the piston 115 and the bore 113.

Configuration of Lubricating Oil

In recent years, in order to further increase the efficiency, measures are being taken, i.e., for example, oil having lower viscosity is used as the lubricating oil 103. In the present disclosure, the lubricating oil 103 used in the refrigerant compressor 100 has low viscosity and high flash point as described above. Specifically, the kinetic viscosity of the lubricating oil 103 at 40° C. falls within a range of 0.1 to 5.1 mm²/s, and the flash point of the lubricating oil 103 is 110° C. or more.

The specific configuration of the lubricating oil 103 according to the present disclosure is not especially limited. The lubricating oil 103 is only required to have the kinetic viscosity that falls within the above range and the flash point that is the above lower limit or more. Typical examples of the lubricating oil 103 include mineral oil, synthetic oil, and a mixture (mixed oil) of the mineral oil and the synthetic oil. The lubricating oil 103 may contain a component other than oily substances, such as the mineral oil and the synthetic oil. Therefore, the lubricating oil 103 according to the present disclosure may be a lubricating oil composition containing at least an oily substance.

A typical example of the lubricating oil 103 according to the present disclosure is the mixed oil constituted by the mineral oil and the synthetic oil. This mixed oil may be constituted by the mineral oil as a major component and the synthetic oil as a subcomponent or may be constituted by the synthetic oil as the major component and the mineral oil as the subcomponent. Or, the mixed oil may be constituted by the mineral oil and the synthetic oil both as the major components. Herein, the content of the mineral oil or the synthetic oil as the major component is only required to be set such that the mineral oil or the synthetic oil is regarded as the “major component” in the entire lubricating oil 103 (lubricating oil composition). Similarly, the content of the oily substance as the subcomponent is only required to be set such that the oily substance is regarded as the “subcomponent” in the entire lubricating oil 103 (lubricating oil composition); and the content of the oily substance as the subcomponent is smaller than the content of the oily substance as the major component.

In the present disclosure, a more specific example of the lubricating oil 103 is the mixed oil containing the mineral oil as the major component and the synthetic oil as the subcomponent. When the entire amount of the lubricating oil 103 is regarded as 100 wt. %, the content of the synthetic oil as the subcomponent is only required to fall within, for example, a range of 0.1 to 40.0 wt. %, preferably a range of 1 to 35 wt. %, more preferably a range of 5 to 25 wt. %. Further, the content of the mineral oil as the major component in the lubricating oil 103 is only required to be larger than the content of the synthetic oil. For example, when the content of the synthetic oil is 40.0 wt. % or less of the entire amount of the lubricating oil 103 as described above, the content of the mineral oil is only required to exceed 40.0 wt. % of the entire amount of the lubricating oil 103 and may be, for example, 50 wt. % or more.

By mixing (blending) the synthetic oil with the mineral oil, the viscosity of the lubricating oil 103 is lowered, and in addition, the flash point of the lubricating oil 103 is adjusted so as not to be lowered. Therefore, when the content of the synthetic oil is set to fall within the above range, the kinetic viscosity of the lubricating oil 103 and the lower limit of the flash point of the lubricating oil 103 can be easily adjusted to fall within the above-described respective numerical ranges. Needless to say, the lubricating oil 103 is not limited to the mixed oil containing the mineral oil as the major component and the synthetic oil as the subcomponent as long as the lubricating oil 103 can be adjusted to have the low viscosity and the high flash point as described above.

The types of the mineral oil and synthetic oil constituting the lubricating oil 103 are not especially limited. General examples of the mineral oil include paraffin mineral oil and naphthenic mineral oil. In the present disclosure, the paraffin mineral oil or the naphthenic mineral oil may be used, or a mixture of the paraffin mineral oil and the naphthenic mineral oil may be used. Further, plural types of paraffin mineral oils having different physical properties may be used in combination. Similarly, plural types of naphthenic mineral oils having different physical properties may be used in combination. Further, a mixture of a combination of different paraffin mineral oils and a combination of different naphthenic mineral oils may be used.

Specific examples of the synthetic oil include polyalphaolefin oil, alkyl benzene oil, ester oil, ether oil, polyalkylene glycol oil, fluorinated synthetic oil, and silicon synthetic oil. However, the synthetic oil is not especially limited. Only one type of synthetic oil may be selected and mixed with the mineral oil, or a combination of plural types of synthetic oils may be mixed with the mineral oil.

In the present disclosure, it is preferable to use at least one selected from the group consisting of ester oil, ether oil, polyalkylene glycol oil, and alkyl benzene oil. By mixing at least one of these synthetic oils with the mineral oil, the kinetic viscosity of the lubricating oil 103 and the lower limit of the flash point of the lubricating oil 103 can be easily adjusted to fall within the above-described respective numerical ranges. Further, depending on the type of the synthetic oil, properties other than the kinetic viscosity and the lower limit of the flash point can be given to the lubricating oil 103. For example, when ester oil having polarity is selected as the synthetic oil and mixed with the mineral oil, the polarity can be given to the lubricating oil 103.

In the present disclosure, the lubricating oil 103 is manufactured by mixing at least the mineral oil and the synthetic oil with each other. With this, as described above, the kinetic viscosity of the lubricating oil 103 at 40° C. is adjusted to fall within a range of 0.1 to 5.1 mm²/s, and the flash point of the lubricating oil 103 is adjusted to 110° C. or more. The kinetic viscosity of the lubricating oil 103 at 40° C. is not especially limited as long as it falls within the above range. However, a preferable example is that the kinetic viscosity of the lubricating oil 103 at 40° C. falls within a range of 0.1 to 4.5 mm²/s, and a more preferable example is that the kinetic viscosity of the lubricating oil 103 at 40° C. falls within a range of 0.1 mm²/s or more and less than 3.0 mm²/s. In the present disclosure, the kinetic viscosity is measured based on JIS K2283.

If the kinetic viscosity of the lubricating oil 103 at 40° C. exceeds 5.1 mm²/s, this does not mean that the viscosity of the lubricating oil 103 is lowered. Therefore, the effect of the increase in the efficiency by the lowering of the viscosity cannot be adequately obtained. In contrast, if the kinetic viscosity of the lubricating oil 103 at 40° C. is less than 0.1 mm²/s, the lubricating effect of the lubricating oil 103 may not be adequately obtained.

Similarly, in the present disclosure, the lower limit of the flash point of the lubricating oil 103 is not especially limited as long as it is 110° C. or more. However, a preferable example is 120° C. or more, and a more preferable example is 150° C. or more. In the present disclosure, the flash point is measured based on JIS K2265. If the lower limit of the flash point of the lubricating oil 103 is less than 110° C., more extreme care against fire is required when handling the lubricating oil 103. In addition, if a special storage condition is not satisfied, the viscosity of the lubricating oil 103 may increase over time. Therefore, the handleability of the lubricating oil 103 deteriorates.

Specifically, if the flash point of the lubricating oil 103 lowers, the amount of low distillation components contained in the lubricating oil 103 increases. Therefore, if the lubricating oil 103 is stored under a normal condition, the low distillation components contained in the lubricating oil 103 may evaporate first, and this may increase the viscosity of the lubricating oil 103 over time. The general lubricating oil 103 is stored under a low-vacuum and high-temperature condition, such as a 10⁻² Pa atmosphere and a temperature range of 40 to 60° C. However, if the flash point of the lubricating oil 103 is low, the low distillation components evaporate under such low-vacuum and high-temperature condition, and this increases the viscosity over time. Therefore, a special storage condition using a chemical filter is required.

It is more preferable that in addition to the range of the kinetic viscosity of the lubricating oil 103 at 40° C. and the lower limit of the flash point of the lubricating oil 103, a predetermined distillation property be satisfied. Specifically, it is preferable that the lubricating oil 103 according to the present disclosure have a distillation property in which a distillation range is 200 to 400° C. (i.e., a distillation property in which an initial boiling point is 200° C., and an end point is 400° C.). In the present disclosure, the distillation property is measured based on JIS K2254.

Since the mineral oil is basically a mixture of many types of oily substances, the mineral oil has a wide variety of distillation properties. However, since the synthetic oil is basically constituted by one type of synthetic compound (or several types of synthetic compounds), one distillation property is specified (or several distillation properties are specified). Therefore, by mixing the synthetic oil with the mineral oil, the distillation property of the lubricating oil 103 that is the mixed oil can be adjusted to fall within the above distillation range. It should be noted that the mineral oil may be refined so as to also fall within the above distillation range according to need.

In the present disclosure, when the lubricating oil 103 satisfies a condition that is the distillation property in addition to basic conditions that are the range of the kinetic viscosity at 40° C. and the lower limit of the flash point, the amount of the low distillation components contained in the lubricating oil 103 can be made smaller. Therefore, the tendency of the lowering of the flash point of the lubricating oil 103 can be suppressed more effectively, and the stability of the lubricating oil 103 can be made satisfactory. As a result, the handleability of the lubricating oil 103 can be made more suitable.

As described above, the lubricating oil 103 according to the present disclosure is the lubricating oil composition constituted by the mineral oil and the synthetic oil and may contain a component other than the mineral oil and the synthetic oil. Specific examples of such component include various additives known in the field of the lubricating oil 103.

The additive is not especially limited but is, for example, at least one of an extreme pressure additive, an oily agent, an antifoaming agent, and a stabilizing agent. By adding such additive to the mixed oil constituted by the mineral oil and the synthetic oil, the property of the lubricating oil 103 improves, and the reliability of the refrigerant compressor 100 improves.

The amount of the additive added (the content of the additive) is not not especially limited. In the present disclosure, the amount of the additive added is only required to fall within a range of 0.1 to 10 wt. % of the entire amount of the lubricating oil 103. If the content of the additive is less than 0.1 wt. % of the entire amount of the lubricating oil 103, the amount of the additive added may be too small, and therefore, the effect of the additive may not be adequately obtained, although it depends on the type of the additive. In contrast, if the content of the additive exceeds 10 wt. % of the entire amount of the lubricating oil 103, the effect corresponding to the amount of the additive added may not be obtained, although it depends on the type of the additive. In addition, since the content of the additive is excessive, this may influence other physical properties of the lubricating oil 103.

In the present disclosure, a typical example of the additive is the stabilizing agent. By adding the stabilizing agent, the physical properties of the lubricating oil 103 having the low viscosity and the high flash point can be satisfactorily stabilized. In the present disclosure, examples of the stabilizing agent include an acid capturing agent and fullerene. When the stabilizing agent is the acid capturing agent, the fullerene, or a combination of the acid capturing agent and the fullerene, the stability of the lubricating oil 103 can be made more satisfactory, and the reliability of the refrigerant compressor 100 can be improved.

The acid capturing agent is used to prevent a case where base oil (i.e., the mixed oil constituted by the mineral oil and the synthetic oil) is deteriorated by water or oxygen, and this increases the acid value. By suppressing the deterioration of the mixed oil (base oil) by the addition of the acid capturing agent, the kinetic viscosity of the lubricating oil 103 at 40° C. can be effectively prevented from falling outside the above range.

The specific type of the acid capturing agent is not especially limited, and a known acid capturing agent can be suitably used. Since the fullerene has an effect of suppressing the lowering of the flash point of the lubricating oil 103, the fullerene can be used as a “flash point lowering suppressing agent.” Therefore, the lowering of the flash point of the lubricating oil 103 can be further effectively suppressed by the addition of the fullerene.

The amount of the acid capturing agent and/or fullerene added as the stabilizing agent is only required to fall within a range of 0.1 to 10 wt. % of the entire amount of the lubricating oil 103. By adjusting the amount of the stabilizing agent added (i.e., the content of the stabilizing agent) within the above range, the properties of the lubricating oil 103 can be improved by an appropriate amount of stabilizing agent. Therefore, the reliability of the refrigerant compressor 100 can be further improved. Especially when the stabilizing agent is the fullerene, it is preferable that the content of the fullerene fall within a range of 0.1 to 5 wt. % of the entire amount of the lubricating oil 103. With this, the stability of the lubricating oil 103 can be made more satisfactory by the fullerene.

Configurations of Resin Members

In the refrigerant compressor 100 according to the present disclosure, as described above, the lubricating oil 103 having the low viscosity and the high flash point is stored in the sealed container 101, and the resin members are included as the members accommodated in the sealed container 101. The amount of oligomer contained in each of the resin members is 2.5 wt. % or less of the entire weight of the resin member. The oligomer is a low molecular component contained in a polymeric material constituting the resin member. The oligomer normally denotes polymer of a relatively small amount of monomers constituting the polymeric material. The range of a specific polymerization degree of the oligomer is not especially specified. However, typical examples include oligomer having a polymerization degree of 100 or less and oligomer having a molecular weight of less than 1,000.

In the present disclosure, the oligomer contained in the resin member is only required to be a component which is extracted by general lubricating oil and has a low polymerization degree. Typically, the oligomer is at least one of dimer, trimer, and tetramer. These oligomers may be contained alone, or at least one of these oligomers may be contained. Each of these oligomers has an especially small molecular weight. Therefore, when general lubricating oil having low viscosity permeates the resin member, the oligomer is easily extracted. However, in the present disclosure, the lubricating oil 103 has the low viscosity and the high flash point. Therefore, even when the oligomer is at least one of the dimer, the trimer, and the tetramer, the oligomer is hardly extracted from the resin member.

As described above, an upper limit of the amount of oligomer contained in the resin member is only required to be 2.5 wt. % or less of the entire weight of the resin member and may fall within a range of 0.01 to 1 wt. % of the entire weight of the resin member. In so-called low oligomer type resin, the content of the oligomer is about 0.2 wt. % of the entire weight. In the present disclosure, the lubricating oil 103 has the low viscosity and the high flash point. Therefore, even if the content of the oligomer in the resin member is larger than that in the low oligomer type resin, the extraction of the oligomer can be effectively suppressed.

In the present disclosure, the density of the resin member is not especially limited. However, typically, it is preferable that the density of the resin member fall within a range of 1.2 to 3.0 g/cm³, and it is more preferable that the density of the resin member fall within a range of 1.3 to 1.6 g/cm³. Generally, when the density of the lubricating oil 103 increases, the lubricating oil 103 hardly permeates the resin member, and therefore, the oligomer is hardly extracted from the resin member. In other words, when the density of the resin member is low, the oligomer is easily extracted by the lubricating oil 103. In the present disclosure, even when the range of the density of the resin member is wide as above, the oligomer is hardly extracted from the resin member by the lubricating oil 103 having the low viscosity and the high flash point.

In the present disclosure, as described above, typical examples of the resin members accommodated in the sealed container 101 include the suction muffler 125, the insulating member attached to the electric element 106, and the cluster 127. These resin members may be constituted only by resin (polymer). However, for example, the resin members may be constituted by composite materials containing a different material, such as a fibrous material or a filler, in addition to the resin. The cluster 127 is, for example, a member made of polyester resin containing glass fibers. Similarly, the suction muffler 125 is, for example, a member made of polyester resin containing glass fibers.

The resin (polymer) constituting the resin member is not especially limited. Specific examples of the resin (polymer) include polyester resin (such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT)), polyamide (PA), polyphenylene sulfide (PPS), and liquid crystal polymer (liquid crystal polyester (LCP)). Since such resin excels in heat resistance, refrigerant resistance, oil resistance, and the like, such resin is preferably used as the material of the resin member accommodated in the sealed container 101. The resin material constituting the resin member is only required to be one type of resin but may be a polymer alloy (polymer blend) prepared by suitably combining two or more types of resin. Further, a known additive may be contained in the resin constituting the resin member.

As described above, examples of the different material contained in the resin member include the fibrous material and the filler. Examples of the fibrous material include an aramid fiber, a nylon fiber, a polyester fiber, a glass fiber, and a carbon fiber. However, the fibrous material is not especially limited. Only one type of fibrous material may be used, or two or more types of fibrous materials may be used suitably in combination. The filler is only required to be in the form of particles or powder, but may be in the form of short fibers. In some cases, the fibrous material is regarded as the filler. Specific examples of the filler include inorganic fillers, such as silica, silicate, clay, plaster, alumina, titanium dioxide, talc, and carbon black. However, the filler is not especially limited.

As above, in the refrigerant compressor 100 according to the present disclosure, the members in the sealed container 101 includes the resin members, and the amount of oligomer contained in the resin member is 2.5 wt. % or less of the entire weight of the resin member. The kinetic viscosity of the lubricating oil 103 in the sealed container 101 at 40° C. falls within a range of 0.1 to 5.1 mm²/s, and the flash point of the lubricating oil 103 is 110° C. or more. With this, the amount of oligomer in the resin member in the sealed container 101 is limited, and the lubricating oil 103 in which the kinetic viscosity falls within the above range and the lower limit of the flash point is the above value is used.

As long as the lubricating oil has a relatively high flash point even when the lubricating oil has low viscosity, the lubricating oil 103 hardly permeates the resin member. Therefore, the oligomer is hardly extracted from the resin member. On this account, even when the lubricating oil 103 having the low viscosity is used, the resin member containing a relatively larger amount of oligomer than before can be used, and a possibility that the deterioration of the seal performance of the suction reed, the clogging of the capillary tube, and the like occur due to the extraction of the oligomer can be effectively suppressed. As a result, even when the lubricating oil 103 having the low viscosity is used, the reliability of the refrigerant compressor 100 can be made satisfactory.

In Embodiment 1, the refrigerant compressor 100 is configured such that the electric element 106 is arranged above the compression element 107. However, needless to say, the refrigerant compressor according to the present disclosure may be configured such that the electric element 106 is arranged under the compression element 107. When a refrigerant compressor to which the present disclosure is applicable is configured to be able to use the above-described lubricating oil 103, such refrigerant compressor can obtain the same operational advantages as Embodiment 1.

As described above, in Embodiment 1, the refrigerant compressor 100 is the reciprocating type. However, needless to say, the refrigerant compressor according to the present disclosure is not limited to the reciprocating type and may be a known type, such as a rotary type, a scroll type, or a vibration type. When a refrigerant compressor to which the present disclosure is applicable is configured to include the resin member as the member accommodated in the sealed container 101 and be able to use the above-described lubricating oil 103, such refrigerant compressor can obtain the same operational advantages as Embodiment 1.

In Embodiment 1, the refrigerant compressor 100 is driven by a commercial power supply. However, the refrigerant compressor according to the present disclosure is not limited to this and may be, for example, inverter-driven at a plurality of driving frequencies. Even when the refrigerant compressor is configured as above, high lubricity can be realized by including the resin member as the member accommodated in the sealed container 101 and using the above-described lubricating oil 103. Therefore, the reliability of the refrigerant compressor can be improved even at the time of low-speed driving in which the amount of oil supplied to the respective slide portions becomes small or at the time of high-speed driving in which the rotational frequency of the electric element increases.

Embodiment 2

In Embodiment 2, one example of a refrigeration device including the refrigerant compressor 100 described in Embodiment 1 will be specifically described with reference to FIG. 2. FIG. 2 schematically shows a schematic configuration of a refrigeration device 200 including the refrigerant compressor 100 according to Embodiment 1. Therefore, Embodiment 2 schematically describes a basic configuration of the refrigeration device 200. However, needless to say, the specific configuration of the refrigeration device 200 is not limited to this.

As shown in FIG. 2, the refrigeration device 200 according to Embodiment 2 includes a main body 206, a partition wall 209, a refrigerant circuit 201 (refrigeration cycle), and the like. The main body 206 is constituted by a heat-insulation box body, a door body, and the like. The box body includes an opening on one surface thereof, and the door body opens and closes the opening of the box body. The inside of the main body 206 is divided by the partition wall 209 into a storage space 207 for articles and a machine room 208. A blower (not shown) is provided in the storage space 207. It should be noted that the inside of the main body 206 may be divided into, for example, spaces other than the storage space 207 and the machine room 208.

The refrigerant circuit 201 (refrigeration cycle) is configured to cool the inside of the storage space 207 and includes, for example, the refrigerant compressor 100 described in Embodiment 1, a heat radiator 202, a decompressor 203, and a heat absorber 204. The refrigerant compressor 100, the heat radiator 202, the decompressor 203, and the heat absorber 204 are annularly connected to one another by a pipe 205. The heat absorber 204 is arranged inside the storage space 207. As shown by broken line arrows in FIG. 2, cooling heat of the heat absorber 204 is stirred by the blower (not shown) so as to circulate in the storage space 207. With this, the inside of the storage space 207 is cooled.

As above, the refrigeration device 200 according to Embodiment 2 includes the refrigerant circuit 201 including the refrigerant compressor 100 according to Embodiment 1. As described in Embodiment 1, the efficiency of the refrigerant compressor 100 is increased by using the lubricating oil 103 having the low viscosity and the high flash point.

In addition, since the lubricating oil 103 having the low viscosity and the high flash point hardly permeates the resin members accommodated in the sealed container 101 of the refrigerant compressor 100, the oligomer is hardly extracted from the resin members. Therefore, a possibility that the deterioration of the seal performance of the suction reed, the clogging of the capillary tube, and the like occur due to the extracted oligomer can be effectively suppressed. With this, the reliability of the refrigerant compressor 100 can be improved.

As above, since the refrigeration device 200 according to Embodiment 2 can reduce power consumption, the energy saving can be realized, and the reliability can be improved.

The refrigeration device 200 described in Embodiment 2 is one example of the refrigeration device according to the present disclosure (i.e., the refrigeration device including the refrigerant compressor according to the present disclosure). Needless to say, the present disclosure is not limited to the refrigeration device 200. Examples of the refrigeration device according to the present disclosure include refrigerators (home use, business use), dehumidifiers, showcases, ice makers, heat pump water heaters, heat pump washing/drying machines, vending machines, and air conditioners.

The present invention is not limited to the above described embodiments and may be modified in various ways within the scope of the claims, and embodiments obtained by suitably combining technical means disclosed in different embodiments and/or plural modified examples are included in the technical scope of the present invention.

From the foregoing explanation, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Therefore, the foregoing explanation should be interpreted only as an example and is provided for the purpose of teaching the best mode for carrying out the present invention to one skilled in the art. The structures and/or functional details may be substantially modified within the scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is widely and suitably applicable to the field of refrigerant compressors using lubricating oil having low viscosity and refrigeration device s including such refrigerant compressors.

REFERENCE SIGNS LIST

-   -   100 refrigerant compressor     -   101 sealed container     -   102 refrigerant gas     -   103 lubricating oil     -   104 stator     -   105 rotor     -   106 electric element     -   107 compression element     -   125 suction muffler (resin member)     -   127 cluster (resin members)     -   200 refrigeration device     -   201 refrigerant circuit     -   202 heat radiator     -   203 decompressor     -   204 heat absorber     -   205 pipe 

1. A sealed refrigerant compressor comprising: a compression element accommodated in a sealed container and configured to compress a refrigerant; and an electric element configured to drive the compression element, wherein: lubricating oil is stored in the sealed container; a resin member is included as a member accommodated in the sealed container; an amount of oligomer contained in the resin member is 2.5 wt. % or less of an entire weight of the resin member; kinetic viscosity of the lubricating oil at 40° C. falls within a range of 0.1 to 5.1 mm²/s; and a flash point of the lubricating oil is 110° C. or more.
 2. The sealed refrigerant compressor according to claim 1, wherein the amount of oligomer falls within a range of 0.01 to 1 wt. % of the entire weight of the resin member.
 3. The sealed refrigerant compressor according to claim 1, wherein the oligomer is dimer, trimer, or tetramer or contains at least one of the dimer, the trimer, and the tetramer.
 4. The sealed refrigerant compressor according to claim 1, wherein at least a stabilizing agent is added as an additive to the lubricating oil, and a content of the stabilizing agent added falls within a range of 0.1 to 10 wt. % of an entire amount of the lubricating oil.
 5. The sealed refrigerant compressor according to claim 4, wherein the stabilizing agent is at least one of an acid capturing agent and fullerene.
 6. The sealed refrigerant compressor according to claim 5, wherein when the stabilizing agent is the fullerene, the content of the fullerene falls within a range of 0.1 to 5 wt. % of the entire amount of the lubricating oil.
 7. The sealed refrigerant compressor according to claim 1, wherein density of the resin member falls within a range of 1.2 to 3.0 g/cm³.
 8. A refrigeration device comprising the sealed refrigerant compressor according to claim
 1. 